Non-contact type IC card

ABSTRACT

In a non-contact type IC card, a re-access inhibition time setting circuit 12 sets a re-access inhibition period of time for inhibiting the re-access for a fixed period of time after an operation of a main circuit 16 is finished. This prevents a double write operation of history in the card due to the re-access in a short period of time. Moreover, two areas 321 and 322 are disposed in a memory 32 to write data alternately in these areas. In a read operation, when data of one of the areas is destroyed, the normal data in the other area is read; whereas, when each data is normal, the data last recorded is read. Consequently, the disabled state of the read operation due to wrong data can be prevented.

TECHNICAL FIELD

The present invention relates to a non-contact type integrated circuit(IC) card not having contact terminals for a power source and forinputting and outputting signals.

BACKGROUND ART

There has been known an IC card which as not contact terminals forreceiving signals from an external device or for outputting signalsthereto via a magnetic or capacitive coupling therewith. When using thenon-contact type IC card, as compared with the card achievingcommunications of signals via contact terminals, the read operation isfacilitated since, for example, when a person having the card in his orher hand approaches the external device, data stored in the card can beread therefrom into the external device. Moreover, there can beprevented such problems associated with the card achieving input andoutput operations of data via contact terminals as a contact failure dueto dirt, erosion, etc. of terminal contact points and wrong operationsdue to a leakage current.

For the read operation of the non-contact type IC card, the card bearerhaving the card with him or her need only approach the reader and thereis unnecessitated a read operation to insert the card into the reader.Consequently, the card is suitable for a check of sequential passage ofmany persons, for example, the card is suitably used as a commuter passor a key for checking entrance an exit for a particular room.

In a case where the non-contact type IC card is adopted as a commuterpass or a key for checking entrance and exit for a room, ID data is readfrom a memory of the IC card for a collation thereof such that when thecollation results in a coincidence, the passage of the gate or theentrance for the room is admitted. At the same time, historical data ofuses of the IC card is written in the memory thereof.

When a non-contact type IC card is brought into an area accessible tothe reader-writer, the collation and the write operation of the historyare accomplished. Since the accessible area has a range of a certainmagnitude, when the card is employed as, for example, a commuter pass,there may occur depending on actions of the card holder a case where anidentical card enters two or more times the area accessible to thereader-writer installed at the gate. Namely, it may possible occur, theuser puts the card into the area, removes the card from the area, andthen puts again the card into the area. In such a case, it is necessaryto avoid the write operation of history in the second access.

Conventionally, in the case above, the second access of an identicalcard is detected by the reader-writer to inhibit the write operation ofnew data on the card. However, since passage of many cards is requiredto be checked in a short period of time at the gate, it is necessary forthe reader-writer, after an access of a card, to wait for passage of asubsequent card. Consequently, there does not exit any marginal timeenough to check the second access.

In consequence, it is desired that the operation of a card is inhibitedfor a fixed period of time after a passage thereof. However, in a cardnot having a power source therein, namely, a card of an external powersupply type, an electromagnetic energy supplied from an external deviceis rectified to obtain a direct-current (dc) voltage necessary for aninternal circuit thereof. Consequently, after the external energy supplyis interrupted, it is difficult to control the operation inhibition fora fixed period of time. For example, after the external energy supply isstopped, the circuit in the card may be operated by energy resultantfrom discharge of electric charges accumulated in a smoothing capacitorof the power source circuit. However, since the operation of the circuitis determined by a value of a current consumed by the circuit and theenergy accumulated in the smoothing capacitor, it is difficult to setthe period for inhibiting the operation.

Moreover, in such a non-contact type IC card, since the contact(approaching) state between the card and the reader-writer cannot befixedly established, communications of data and power source become tobe unstable in some cases. For example, in a card of the external powersupply type which receives supply of power via energy such as anelectromagnetic field from an external power source, the card issupplied with power only when the card is in the proximity of thereader-writer. When the card is apart from the reader-writer, the poweris not supplied thereto. In consequence, in a case where the bearer ofthe card puts the card close to the reader-writer to write data receivedfrom the reader-writer in the memory of the card, when the contact stateis changed because the distance between the card and the reader-writeris increased due to movement or the like of the bearer, the power supplyfrom the reader-writer to the card is interrupted. Consequently, thewrite operation of data in the memory of the card is stopped at anintermediate point and hence data is stored in the memory in anincomplete state.

Since such incomplete data is directly stored in the memory, when thedata is read therefrom by the reader-writer, it is impossible toaccomplish a predetermined check operation. For example, when the cardis adopted as a commuter pass, the states of the pass such as a periodthereof, a valid period thereof, a station name where the bearer tookthe train, and time when the bearer took the train are required to beaccurate in any case. Otherwise, there arises a problem that theessential object of the card cannot be achieved.

It is therefore an object of the present invention to provide anon-contact type IC card guaranteeing the normal operation even when anabnormality occurs in an access operation between the card and theexternal device, thereby solving the problems of the non-contact type ICcard.

Namely, the present invention aims at providing a non-contact type ICcard capable of preventing inappropriate data from being written thereineven when the card enters an area accessible to the external device fora plurality of times at a short interval of time.

Moreover, another object of the present invention is to provide anon-contact type IC card guaranteeing the normal operation even when anabnormality occurs in the contact state during a write operation of datafrom the external device.

DISCLOSURE OF THE INVENTION

In accordance with the present invention, a non-contact type IC cardachieving communications of signals with an external device in anoncontact manner includes main circuit means for conducting variousoperations based on functions of the IC card, operation inhibitionsignal generating means for creating an operation inhibition signal toinhibit the operation of the main circuit means for a predeterminedperiod of time, and control means for controlling the main circuit meansand the operation inhibition signal generating means. The control meansoperates the operation inhibition signal generating means when theoperation of the main circuit means is finished and inhibits theoperation of the main circuit means for a predetermined period of timeaccording to the operation inhibition signal from the operationinhibition signal generating means.

In accordance with the present invention, when an operation of the maincircuit means is finished, the operation inhibition signal generatingmeans operates to create an operation inhibition signal, therebyinhibiting the operation of the main circuit means for a predeterminedperiod of time. In consequence, in a case where the card enters an areaaccessible to the external device a plurality of times during a shortperiod of time, the second and subsequent accesses can be inhibited andhence the improper operation due to the plural accesses can be avoided.Moreover, since the inhibition of such accesses need not be monitored bythe external device, the load imposed on the external device can beminimized.

In accordance with the present invention, a non-contact type IC cardincludes communicating means for communicating signals with an externaldevice in a non-contact manner, a memory for storing therein data sentfrom the external device, and control means for controlling operationsof the communicating means and the memory. The memory has an areasubdivided into a plurality of areas for storing therein data sent fromthe external device, and the control means reads, when the data is to beread from the memory, the data from one of the plural areas in which thedata is normally stored.

In accordance with the non-contact type IC card of the presentinvention, an area of a memory for storing therein data sent from theexternal device is subdivided into a plurality of areas such that whenreading data from the memory, the data is read from an area of theplural areas in which the data is normally stored. In consequence, evenwhen the data recorded in one of the areas is wrong, the data can beread from the other area. Consequently, even when an abnormality occursin a write operation of data, the data can be read therefrom.

In consequence, a write operation of wrong data or absence of recorddata which occurs when the card holder moves therewith at a high speedcan be coped with by executing a predetermined processing with thenormal data read from the memory.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram showing an embodiment of anon-contact type IC card in accordance with the present invention;

FIG. 2 a circuit diagram showing a specific example of the card of FIG.1;

FIG. 3 is a timing chart showing the operation of the circuit of FIG. 2;

FIG. 4 is a timing chart showing the operation of the control circuit ofFIG. 2;

FIG. 5 is a block diagram showing another embodiment of a non-contacttype IC card in accordance with the present invention;

FIG. 6 shows a write operation of data in a memory of the card of FIG.5;

FIG. 7 shows a write operation of data in a memory of the card of FIG.5;

FIG. 8 shows a write operation of data in a memory of the card of FIG.5;

FIG. 9 shows a write operation of data in a memory of the card of FIG.5;

FIG. 10 is a flowchart showing the operation of the card of FIG. 5;

FIG. 11 is a flowchart showing the operation of the card of FIG. 5;

FIG. 12 is a flowchart showing the operation of the card of FIG. 5; and

FIG. 13 is a flowchart showing the operation of the card of FIG. 5.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring next to the accompanying drawings, description will be givenin detail of a non-contact type IC card in accordance with the presentinvention.

FIG. 1 shows an embodiment of a non-contact type IC card in accordancewith the present invention. This IC card is an IC card of an externalpower supply type receiving power supply from an external device. Inthis connection, portions not directly related to the present inventionare not shown in this embodiment.

The card has a power source circuit 10. The power source circuit 10 is apower supply circuit for transmitting power supplied from areader-writer to the respective components of the card. The power sourcecircuit 10 is coupled with the reader-writer via a magnetic couplingshown in the diagram or a capacitive coupling not shown therein toreceive power supplied from the reader-writer.

The power source circuit 10 is connected to a main circuit 16. The maincircuit 16 is a circuit accomplishing operations according to variousfunctions of the card and is constituted with a central processing unit(CPU), a memory, etc. For example, as shown in FIG. 5, there areincluded a memory 32 and a memory control section 36.

The main circuit 16 has a function to read, when the card is put by thebearer into an area accessible to the reader-writer, ID data from thememory 16 to output the data to the reader-writer and/or a function tocollate ID data sent from the reader-writer with data stored in thememory 32. Moreover, the main circuit 16 writes in the memory 32, afterthe passage of the bearer is admitted by the reader-writer as a resultof such a collation of the ID data, an indication that the passage isadmitted by the data sent from the reader-writer.

The card in addition has a re-access inhibition time setting circuit 12.The circuit 12 is connected to the power source circuit 10 to set aperiod of time for inhibiting a re-access based on a voltage suppliedfrom the power source circuit 10 and a control signal sent from thecontrol circuit 14 and then outputs a re-access inhibition time settingsignal to the control circuit 14.

The control circuit 14 is connected to the circuit 12 and the maincircuit 16 to inhibit the operation of the main circuit 16 for apredetermined period of time according to the re-access inhibition timesetting signal outputted from the circuit 12. Furthermore, the controlcircuit 14 controls, in accordance with an access operation terminatingsignal transmitted from the main circuit 16, the setting operation ofthe circuit 12.

FIG. 2 shows a more specific construction of the circuit of FIG. 1. Fourdiodes D1, D2, D3, and D4; two capacitors C1 and C2; and a regulator 20are disposed as elements corresponding to the power source circuit 10 ofFIG. 10. Electric energy supplied from the reader-writer via a coil L isrectified by the diodes D1 to D4 and the regulator 20.Alternating-current components are removed therefrom by the capacitorsC1 and C2 such that the resultant signal is sent to the main circuit 1and the re-access inhibition time setting circuit 12.

The circuit 12 possesses a transistor Q. The transistor Q has an emitterregion connected to an output of the power source circuit 10 and a baseregion which is connected via a resistor R2 to the output from the powersource 10 and which is connected via a resistor R4 to an output of thecontrol circuit 14. The transistor Q has a collector region linked withan anode of the diode D5 having a cathode connected to a resistor R1 anda capacitor C3. Other terminals respectively of the resistor R1 and thecapacitor C3 are grounded. The cathode of the diode D5 is furtherconnected to a gate region of an field-effect transistor (FET) of ann-type channel 24. The FET 24 has a drain region which is linked via aresistor R3 to an output of the power source circuit 10 and which islinked to a Schmitt trigger circuit 22, whereas the FET 24 has a sourceregion grounded. The Schmitt trigger circuit 22 has an output connectedto an input of the control circuit 14.

Referring to the timing chart of FIG. 3, the operation of the circuit 12will be described. In a case where the card is used as a commuter passand is put into an accessible area of the reader-writer at a gate twicein a short period of time, the circuit 12 sets an inhibition time forinhibiting the second access.

At a point A of FIG. 2, power as indicated by A in FIG. 3 is supplied asan output from the power source circuit 10. Namely, when the card entersthe accessible area of the reader-writer twice (at points of time t1 andt4), energy is supplied at each point of time from the reader-writer viathe power supply circuit 10. When power is supplied at the point A, thepower is fed to the main circuit 16, thereby enabling the main circuit16 to operate. During the operation of the main circuit 16, as indicatedby B in FIG. 3, the main circuit 16 is powered and a signal B denotingthat the main circuit 16 is operable is delivered via the resistor R4 tothe base region of the transistor Q (time t1). Consequently, thetransistor Q is in a non-conductive state and the power supplied to thepoint A is not fed to a point C. The potential of the point C is henceat a ground level as designated by C in FIG. 3. In consequence, sinceany signal is not inputted to the gate region of the FET 24, the FET 24is in a non-conductive state and a point D of the drain region of theFET 24 is supplied with the output from the power source circuit 10 asindicated by D in FIG. 3. As a result, the output from the Schmitttrigger circuit 22 is also as denoted by E in FIG. 3 and the output E istransmitted to the control circuit 14. The control circuit 14 outputs,according to the output E, a signal allowing the operation of the maincircuit 16 to the main circuit 16.

When the operation of the main circuit 16 is finished (time t2), theoutput of the signal B from the control circuit 14 is stopped. This setsthe base region of the transistor Q to a low level and hence thetransistor Q becomes to be conductive, which increases the potential atthe point C as denoted by C in FIG. 3. At the time t3 when the powersupply A from the power source circuit 10 is interrupted, the power fromthe power source circuit 10 is not supplied to the point C. However,according to a discharging operation of electric charge accumulated inthe capacitor C3 during the power supply period, the potential of thepoint C is gradually decreased in accordance with the time constant ofthe capacitor and the resistor as indicated by C in FIG. 3.

At a point of time T4, when the card is again put into the accessiblearea of the reader-writer and the second power is supplied from thepower source circuit 10, a signal B indicating that power can besupplied to the main circuit 16 is sent from the control circuit 14 tothe transistor Q, which sets the transistor Q to a non-conductive state.In consequence, the point C is kept remained in a state where power isnot supplied from the power source circuit 10 and hence the potential ofthe point C continues lowering as shown in FIG. 3. As a result, sincethe potential inputted to the gate region of the FET 24 continuesdecreasing and the current flowing from the drain region to the sourceregion of the FET 24 is minimized, the potential of the point D isgradually increased. In consequence, the voltage D inputted to theSchmitt trigger circuit 22 is gradually increased, at a point of time t5where the voltage D exceeds the predetermined value, a signal E isoutputted from the Schmitt trigger circuit 22. According to this outputE, the control circuit 14 outputs a signal allowing the operation of themain circuit 16 to the main circuit 16.

As above, after the output E from the Schmitt trigger circuit 22 is setto a high level, the operation of the main circuit 16 is allowed.Consequently, after the first operation (access to the reader-writer) ofthe main circuit 16 at the point of time t2 is finished, the operationof the main circuit 16 is not allowed until a point of time t5. Inconsequence, even in a case where the card is put to the accessible areaat the time t4 to supply power from the power source circuit 10, themain circuit 16 does not achieve any operation. As above, after thefirst access is terminated, the access to the reader-writer can beinhibited for a fixed period of time.

Subsequently, the operation of the control circuit 14 will be describedby reference to the flowchart of FIG. 4. Whether or not power is beingsupplied is judged (step 102). If this is not the case, a wait operationis effected until the power-on state occurs. If the power is beingsupplied, it is assumed that the card has entered the accessible area ofthe reader-writer and a check is made to determine whether or not thepoint of time is during the re-access inhibition period (step 104). Ifthis is the case, whether or not the power is off is judged (step 106).If the power is not off, a wait operation is achieved until the power isturned off. When the power is turned off, it is assumed that the card isremoved from the accessible area of the reader-writer and control isreturned to the first step 102.

In the step 104, if the current point is not in the re-access inhibitionperiod, it is assumed that the access to the reader-writer becomes to bepossible and then a predetermined data communication is achieved withthe reader-writer (step 108). Whether or not the data communication hasbeen completed is judged (step 110). If this is the case, the re-accessinhibition period is set (step 112). Thereafter, whether or not thepower is turned off is checked (step 114). If the power is not turnedoff, a wait operation is executed until the power is turned off. Whenthe power is turned off, it is assumed that the card is removed from theaccessible area of the reader-writer and then control is returned to thefirst step 102.

Also in the case where the data communication is not completed in thestep 110, whether or not the power is turned off is judged (step 116)such that if this is the case, control is passed to the step 102.

As above, in accordance with the card of the present embodiment, afteran access is finished, the re-access can be inhibited for a fixed periodof time. In consequence, in a case where the card enters the accessiblearea of the reader-writer two or more times in a short period of time,the second and subsequent accesses to the reader-writer can be inhibitedand hence the inappropriate operation due to a plurality of accesses canbe prevented. Moreover, since the card has the function to inhibit theaccess, the operation to inhibit the re-access of the card need not beachieved by the reader-writer, thereby minimizing the load imposed onthe reader-writer.

In accordance with the card, in a case where, for example, it isnecessary at a gate to check passages of many cards in a short period oftime, the reader-writer is not required to check the re-access.Consequently, after an access of a card, the reader-writer canimmediately await a passage of the next card, which enables the accessesto many cards in a smooth manner.

In accordance with the present invention as described above, when theoperation of the main circuit means is terminated, the operationinhibition signal generating means operates to create an operationinhibition signal, thereby inhibiting the operation of the main circuitmeans for a predetermined period of time. Consequently, in a case wherethe card enters an area accessible to the external device a plurality oftimes in a short period of time, the second and subsequent accesses canbe inhibited, thereby preventing the inappropriate operation due to theplural accesses. Furthermore, since the access inhibition above need notbe monitored by the external device, the load on the external device canbe reduced.

FIG. 5 shows another embodiment of a non-contact type IC card inaccordance with the present invention. This card 30 includes a memory 32of an electrically erasable programmable ROM (EEPROM) or the like. Thememory 32 has two areas 321 and 322 in this embodiment. As will bedescribed later, in the IC card of the embodiment, data items arerecorded in these two areas 321 and 322 together with numbers indicatingsequence numbers of the data item write operation. In a data readoperation, the data items are read by referencing the numbers in theareas so that data is read from one of the areas last undergone arecording operation. Moreover, in a case where data recorded in eitherone of the two areas 321 and 322 is in a destroyed state due to, forexample, an interruption of a data write operation, data recorded in theremaining one thereof is read. With the provision of two areas, evenwhen an abnormality occurs during a data write operation in one of theareas of the card, data can be read from the remaining area for usethereof, which thereby prevents an operation failure. In thisconnection, the number of areas disposed in the memory 32 is not limitedto two, namely, the number may be three or more.

The card 30 further include a read area deciding section 34 connected tothe memory 32. The read area deciding section 34 judges to determinefrom which one of the two areas 321 and 322 of the memory data is to beread. The memory 32 and the section 34 are connected to a memory controlsection 36. The section 36 controls according to commands an operationto write in the memory 32 data sent from a reader-writer, not shown, viaa noncontact terminal 40 and a modulating and demodulating section 38and an operation to read data stored in the memory 32 so as to feed thedata to the reader-writer. The memory control section 36 achieves acontrol operation to record data sent from the reader-writer alternatelyin the two areas 321 and 322 together with the numbers indicating therecording order. Moreover, particularly, the section 36 controls a dataread operation to read data from an area determined by the section 34.

The modulating and demodulating section 38 modulates data outputted fromthe memory control section 36 to the reader-writer and demodulates datainputted from the reader-writer via the noncontact terminal 40. Theterminal 40 is used to communicate data with the reader-writer, notshown, in a noncontact manner.

The power source circuit 10 is, like in the embodiment described above,a circuit to send power supplied from the reader-writer to therespective sections of the card 30. The power source circuit 10 iscoupled with the reader-writer via a magnetic coupling shown in thediagram or a capacitive coupling, not shown, to receive power suppliedfrom the reader-writer.

Referring to the changes in the recording state of the memory 32 shownin FIGS. 6 to 9, description will be given of the operation to writedata in the memory 32. In each of the areas 321 and 322, there aredisposed the areas including a data area D in which data is recorded, anumber area N in which a number of a write sequence of data is recorded,and a check code area in which a check code is recorded.

Immediately after the card 30 is issued, as shown in FIG. 6, there arerecorded data 1, "0" as the number denoting the write sequence, and apredetermine code C such as a DDC code in the data areas D, N, and C,respectively. The data recorded in the data area D is one of variouskinds of data items such as an ID number communicated between the ICcard and the reader-writer. The number indicating the write sequencerecorded in the number area N indicates a write sequential number ofdata recorded in the data area D of each of two areas. As shown in FIG.6, immediately after the issuance of the card 30, "0" is recorded as aninitial value. The check code recorded in the check code area C is usedto determine whether or not the data is normal, and one of the knownvarious codes is employed.

For the data to be recorded in the data area D, data inputted from thereader-writer via the noncontact terminal 40 is demodulated by themodulating and demodulating section 38 and is then sent from the memorycontrol section 36 to the memory 32 so as to be stored therein.Moreover, the data to be recorded in the data area D and the code to berecorded in the check code area C are generated by the memory controlsection 36 and is then sent to the memory 32 to be stored therein.

Immediately after the issuance of the card 30, any data is not recordedin the area 322. Consequently, in a data read operation, the data in thearea 322 is assumed to be in a destroyed state by the read area decidingsection 34 such that data recorded in the area 321 is read by the memorycontrol section 36.

Next, as shown in FIG. 7, a first data write operation is accomplishedin the area 322. As shown in this diagram, data 2 is recorded in thedata area D and a number "1" is recorded as a data record sequentialnumber in the number area N. In the check code area C, there is recordeda predetermined check code. In a state in which the first data writeoperation has been conducted, the section 34 compares the numberrecorded in the number area N of the area 321 with that recorded in thenumber area N of the area 322 to determine that the data recorded in thearea 322 is the latest data. Consequently, in the data read operation,the data 2 recorded in the area 322 is read.

In addition, as shown in FIG. 8, a second data write operation isachieved in the area 321. The data write operations are conducted asabove in the two areas 321 and 322 in an alternating manner.

As a result of the second data write operation of FIG. 8, in the area321, data 3 is recorded in the data area D, a number "2" is recorded asa data record sequential number in the number area N, and apredetermined check code is recorded in the check code area C. In astate where the second data write operation is achieved as above, thedata recorded in the area 321 is the latest data and hence the data 3recorded in the area 321 is read in the data read operation.

Subsequently, in a similar manner, data write operations are conductedin the two areas 321 and 322 in an alternating fashion. For example, asshown in FIG. 9, in a case where after the n-th data is correctlywritten in the area 322, if the (n+1)-th data write operation in thearea 321 results in a failure, the data in the area 321 is in thedestroyed state. Consequently, in this case, the read area decidingsection 34 assumes, without achieving the comparison between the numbersstored in the number areas N of the two areas, that the data recorded inthe area 322 is the latest data such that the data is read by the memorycontrol unit 36.

Subsequently, the operation of the IC card 30 will be describedaccording to the flowcharts shown in FIGS. 10 to 13.

First, in a step 202 of FIG. 10, normality or abnormality of the data inthe two areas 321 and 322 of the memory 32 is judged by checking thecheck code by the read area deciding section 34. Whether or not the dataof each of the areas 321 and 322 is wrong (NG) is judged (step 204). Ifthis is the case, the section 34 outputs a signal of the condition tothe section 36, which then proceeds to the processing of FIG. 11.

In a step 230 of FIG. 11, the section 36 judges to determine whether ornot a read operation is to be executed. If this is the case, a signalindicating that the memory 32 is in the destroyed state is outputtedfrom the section 36 to the reader-writer (step 232). Otherwise, whetheror not a write operation is to be executed is judged (step 234). If thisis the case, data is written in the data area D of the area 321 and anumber "0" is recorded in the number area N (Step 236). If the writeoperation is not assumed in the step 234, control is returned to thestep 230 to repeatedly achieve the same operation.

In the step 204 of FIG. 10, if data of both of the two areas 321 and 322are not wrong (NG), control is passed to a step 206 such that thesection 34 checks to determine whether or not the data in the area 321is NG. If this is the case, control is transferred to the processing ofFIG. 12.

In a step 240 of FIG. 12, the section 36 judges to decide whether or nota read operation is to be executed. If this is the case, data recordedin the area 322 is read to be transmitted to the reader-writer (step242). Otherwise, whether or not a write operation is to be achieved isjudged (step 244). If this is the case, data is written is the data areaD of the area 321 and the number to be written in the number area N isupdated (step 246). In the step 244, if the write operation is notassumed, control is returned to the step 240 to repeatedly accomplishthe same operation.

In the step 206 of FIG. 10, when the data in the area 321 is not NG,control proceeds to a step 208 in which the section 34 judges todetermine whether or not the data in the area 322 is NG. If this is thecase, control is passed to the processing of FIG. 13. In a step 250 ofFIG. 13, the section 36 judges to decide whether or not a read operationis to be executed. If this is the case, data recorded in the area 321 isread to be transmitted to the reader-writer (step 252). In the case of awrite operation, data is written in the data area D of the area 322 anda number to be written in the number area N is updated (step 256). Inthe step 254, when the write operation is not assumed, control isreturned to the step 250 to repeatedly accomplish the same operation.

In the step 208 of FIG. 10, when the data in the area 322 is not NG,control proceeds to a step 210 such that the section 34 judges todetermine whether or not the number recorded in the number area N ofeach of the areas is successive. If this is not the case, data of eachof the areas is assumed to have been destroyed and control istransferred to the processing of FIG. 11. If the number is consecutive,the number of the area 321 is compared with that of the area 322 (step212). If the number of the area 321 is larger than that of the area 322,the section 34 assumes that the data recorded in the area 321 is thelatest data and then passes control to the processing of FIG. 13 to readdata from the area 321. In the step 212, if the number of the area 321is smaller than that of the area 322, the section 34 assumes that thedata recorded in the area 322 is the latest data and then transferscontrol to the processing of FIG. 12 to read data from the area 322.

As above, according to the IC card of the present embodiment, the memory32 is subdivided into two areas 321 and 322 to record data alternatelyin these areas with a number indicating a write sequential numberassigned to each of the recorded data. In consequence, even when datarecorded in one of these areas is wrong, data can be read from the otherarea and hence the data read operation is not prevented even when anabnormality occurs in the data write operation.

For example, when the card is adopted as a commuter pass or a key forentrance and exit for a place, in a case where the holder moves at ahigh speed while putting the card in the proximity of the reader-writer,the power supply from the reader-writer is interrupted at anintermediate point of the data write operation and hence the data thuswritten is wrong. However, also in such a case, data such as the gatecheck state is kept in the other area; consequently, the disabled stateof the data read operation can be avoided by reading the recorded data.

In addition, when the data recorded in each of the areas is normal, thenumbers recorded in the number areas N of the two areas are comparedwith each other to select and to read the last recorded data.Consequently, although data items are recorded in two areas, it will notoccur that the old data is read by mistake.

In accordance with the non-contact type IC card of the presentinvention, the memory has an area subdivided into a plurality of areasfor storing therein data sent from an external device. In a case of anoperation to read data from the memory, the data is read from one of theareas in which the data is normally recorded. Consequence, also in acase where data recorded in an area is wrong, data can be read fromanother area and hence the data read operation is not disabled even whenan abnormality takes place in the data write operation.

Consequently, a write operation of wrong data and absence of record datacaused, for example, when the card holder moves at a high speed with thecard can be coped with by reading the normal data so as to conduct apredetermined processing.

FIG. 14 shows further another embodiment of a non-contact type IC cardin accordance with the present invention. This card includes bothconfigurations of the cards shown in FIGS. 1 and 5. According to thiscard, as can be appreciated from the explanation above, after an accessis finished, a re-access can be inhibited for a fixed period of time. Inconsequence, when the card enters an accessible area of thereader-writer two or more times in a short period of time, the secondand subsequent accesses to the reader-writer can be inhibited and hencean inappropriate operation due to the plural access can be prevented.Moreover, since the card has a function to inhibit the access, theoperation to inhibit the re-access of the card need not be accomplishedby the reader-writer and hence the load imposed on the reader-writer canbe mitigated.

Furthermore, a memory 32 is subdivided into two areas 321 and 322 suchthat data is recorded alternately in these areas with a numberindicating a write sequence number assigned to the recorded data.Consequently, even when data recorded in one of the areas is wrong, datacan be read from the other area and hence the data read operation is notdisabled even when an abnormality occurs in the data write operation.

Moreover, in a case where data written in each of the areas is normal,the numbers recorded in the number areas N of the two areas are comparedwith each other so as to select and to read the latest record data.Consequently, although data items are recorded in two areas, the olddata cannot be read by mistake.

In this regard, the respective embodiments have been described inconjunction with non-contact type IC card of an external power supplytype to which power is supplied from an external device. However, thepresent invention is not restricted by the IC card of the external powersupply type and is also applicable to an IC card of an integrated powersupply type. In a case of the IC card of the integrated power supplytype, there is disposed an integrated power source in addition to thepower source circuit 10 above.

I claim:
 1. A non-contact type IC card that communicates signals with anexternal device in a non-contact manner, comprising:main circuit meansfor conducting various operations based on functions of said non-contacttype IC card; operation inhibition signal generating means for creatingan operation inhibition signal to inhibit an operation of said maincircuit means for a predetermined period of time; and control means forcontrolling said main circuit means and said operation inhibition signalgenerating means, wherein said control means operates said operationinhibition signal generating means when said operation of said maincircuit means is finished and inhibits said operation of said maincircuit means for a predetermined period of time according to saidoperation inhibition signal from said operation inhibition signalgenerating means.
 2. A non-contact type IC card in accordance with claim1, further comprising power source circuit means for receiving powersupplied from an external device and supplying said power to eachsection of said non-contact type IC card,wherein said main circuit meansand said operation inhibition signal generating means operate byreceiving power from said power source circuit means.
 3. A non-contacttype IC card in accordance with claim 2, said operation inhibitionsignal generating means comprising means for accumulating said powersupplied from said power source circuit means and discharging said poweraccording to a predetermined time constant, means for inverting anoutput from said accumulating means to obtain a gradually increasingvoltage, and means for outputting said operation inhibition signal whensaid voltage obtained from said inverting means exceeds a predeterminedvalue.
 4. A non-contact type IC card in accordance with claim 3, saidoperation inhibition signal generating means further comprising aswitching transistor operated by a control signal from said controlmeans to control said accumulation of power supplied from said powersource circuit means in said accumulating means.
 5. The non-contact typeIC card of claim 3, wherein said outputting means comprises a Schmitttrigger circuit.
 6. The non-contact type IC card of claim 1, whereinsaid operation inhibition signal generating means comprises:means foraccumulating electrical power supplied from a power source circuit andfor discharging said electrical power according to a predetermined timeconstant; means for inverting an output from said accumulating means toobtain a gradually increasing voltage; and means for outputting saidoperation inhibition signal when said voltage obtained from saidinverting means exceeds a predetermined value.
 7. The non-contact typeIC card of claim 6, further comprising means for receiving saidelectrical power from an external device.
 8. The non-contact type ICcard of claim 7, wherein said electrical power from said external deviceis magnetically coupled to said non-contact type IC card.
 9. Thenon-contact type IC card of claim 7, wherein said electrical power fromsaid external device is capacitively coupled to said non-contact type ICcard.
 10. A non-contact IC card, comprising:means for communicatingsignals with an external device in a non-contact manner; a memory forstoring data sent from said external device; and means for controllingoperations of said communicating means and said memory, wherein saidcontrol means comprises means for reading, when data is to be read fromsaid memory, data from one of a plurality of areas in which data isnormally stored, and means for inhibiting an operation of saidnon-contact IC card for a predetermined period of time upon anoccurrence of a predetermined event.
 11. A non-contact type IC card inaccordance with claim 10, wherein said controlling means reads, whenthere are said plurality of areas in which data is normally stored, datafrom one of said plurality of areas in which data is last stored.
 12. Anon-contact hype IC card in accordance with claim 11, further comprisingmeans for recording number data in each of said plurality of areas ofsaid memory representing a recording sequence number of said data.
 13. Anon-contact type IC card in accordance with claim 10, further comprisinga power source circuit for receiving power from an external device andsupplying said power to said communicating means, said memory and saidcontrol means.
 14. A non-contact type IC card, comprising:means forcommunicating signals with an external device in a non-contact manner; amemory for storing data sent from said external device; first controlmeans for controlling operations of said communicating means and saidmemory; operation inhibition signal generating means for generating anoperation inhibition signal for inhibiting said operations of saidcommunicating means, said memory, and said first control means; andsecond control means for controlling said operation inhibition signalgenerating means, wherein said memory has an area subdivided into aplurality of areas for storing therein data sent from said externaldevice; said first control means reads, when data is to be read fromsaid memory, said data from one of said plurality of areas in which datais normally stored; and said second control means operates saidoperation inhibition signal generating means when said operations ofsaid communicating means, said memory, and said first control means arefinished and inhibits for a predetermined period of time said operationsof said communicating means, said memory, and said first control meansaccording to said operation inhibition signal from said operationinhibition signal generating means.
 15. A data storage device thatprevents the exchange of erroneous data with an external device,comprising:a memory for storing data; means for exchanging data betweensaid memory and said external device in a non-contact manner; and meansfor inhibiting an operation of said memory and said data exchangingmeans for a predetermined period of time after said data storage devicecompletes an exchange of data with said external device.
 16. The datastorage device of claim 15, further comprising means for receivingelectrical power supplied from an external device, said power beingsupplied to said memory, said exchanging means and said inhibitingmeans.
 17. The data storage device of claim 16, wherein said electricalpower supplied from said external device is magnetically coupled to saiddata storage device.
 18. The data storage device of claim 16, whereinsaid electrical power supplied from said external device is capacitivelycoupled to said data storage device.
 19. The data storage device ofclaim 15, wherein said inhibiting means comprises means for accumulatingelectrical power supplied from an external device, said accumulatedelectrical power being discharged according to a predetermined timeconstant.
 20. The data storage device of claim 19, furthercomprising:means for inverting an output of said accumulating means toobtain a gradually increasing voltage; and means for triggering saidinhibiting means to output an inhibiting signal when said voltage ofsaid inverting means exceeds a predetermined value.
 21. The data storagedevice of claim 15, further comprising a processing unit that controlsvarious operations of said memory, said exchanging means and saidinhibiting means.